An embodiment relates generally to vision monitoring systems for tracking humans.
Manufacturing and assembly operations employ the use of safety devices to prevent harm to an operator working in the vicinity of the equipment. A plurality of sensors and other devices are disposed throughout a manufacturing or assembly process for sensing the operator's proximity to the equipment. In response to the operator being within a predetermined distance from the equipment, the equipment is shut down or prevented from executing a task due to the operator being within a caution zone of the equipment. The caution zone is a predefined area or region in which safety concerns are taken into consideration based on proximity of the operator to the equipment where a potential injury to an operator could occur.
The following are examples of safety devices used to detect the operator proximity to the equipment. Floor mats are utilized to sense whether a respective operator is standing on or off the floor mat. The floor mat is positioned at a predetermined distance from the equipment such that if the operator is standing on the floor mat, then the operator is considered being at an acceptable distance from the equipment for the assembly or manufacturing operations to continue. Another safety sensing device includes a light curtain sensor. The light curtain consists of an emitter array provided for emitting a signal and a receiver array for receiving the emitted signal. If an object is detected between the pair of sensors, then the equipment is immediately stopped and will not proceed with a next operation due to the sensors indicating that the operator is in too close of a proximity to the automated moveable equipment.
Other safety systems are known to utilize a vision-based sensing system. Vision-based sensing systems utilize a camera viewing a predefined area that surrounds the equipment. If the operator enters the predefined area, then intrusion is detected and the machine shuts down. However, shutting down the equipment is costly as it disrupts the flow and output of the assembly/manufacturing process. Typically, once the assembly/manufacturing process is interrupted, the machinery and controls must be reset to restart the process. Moreover, current safety systems such as current vision-based systems only sense the presence of an object entering the caution zone area and do not distinguish between a human and a non-human object. Therefore, these systems enforce exclusion zones where any object, including non-human objects, that are moving within the designated area are subject to stopping assembly/manufacturing process. As a result, the use of these conventional systems in a process setting that significantly mixes people and automation without hard guarding would result in excessive false alarms and nuisance trips that are costly in terms of productivity, time, and money.